<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=11"/>
<meta name="generator" content="Doxygen 1.9.4"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>Flow-IPC: shm/stl/stateless_allocator.hpp Source File</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/searchdata.js"></script>
<script type="text/javascript" src="search/search.js"></script>
<link href="doxygen.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
 <tbody>
 <tr id="projectrow">
  <td id="projectalign">
   <div id="projectname">Flow-IPC<span id="projectnumber">&#160;1.0.2</span>
   </div>
   <div id="projectbrief">Flow-IPC project: Full implementation reference.</div>
  </td>
 </tr>
 </tbody>
</table>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.9.4 -->
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&amp;dn=expat.txt MIT */
var searchBox = new SearchBox("searchBox", "search",'Search','.html');
/* @license-end */
</script>
<script type="text/javascript" src="menudata.js"></script>
<script type="text/javascript" src="menu.js"></script>
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&amp;dn=expat.txt MIT */
$(function() {
  initMenu('',true,false,'search.php','Search');
  $(document).ready(function() { init_search(); });
});
/* @license-end */
</script>
<div id="main-nav"></div>
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
     onmouseover="return searchBox.OnSearchSelectShow()"
     onmouseout="return searchBox.OnSearchSelectHide()"
     onkeydown="return searchBox.OnSearchSelectKey(event)">
</div>

<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0" 
        name="MSearchResults" id="MSearchResults">
</iframe>
</div>

<div id="nav-path" class="navpath">
  <ul>
<li class="navelem"><a class="el" href="dir_ddb0f12d0722949f40b2818843b69123.html">shm</a></li><li class="navelem"><a class="el" href="dir_6227a2031bab796131cf8c4b0b895649.html">stl</a></li>  </ul>
</div>
</div><!-- top -->
<div class="header">
  <div class="headertitle"><div class="title">stateless_allocator.hpp</div></div>
</div><!--header-->
<div class="contents">
<a href="stateless__allocator_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow-IPC: Shared Memory</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="arena__activator_8hpp.html">ipc/shm/stl/arena_activator.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span> </div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceipc_1_1shm_1_1stl.html">ipc::shm::stl</a></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span>{</div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span> </div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="comment"></span> </div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment">/**</span></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment"> * Stateless allocator usable with STL-compliant containers to store (or merely read) them directly in SHM in</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"> * a given SHM-aware `Arena`.  Please read background in shm::stl namespace doc header (shm_stl_fwd.hpp).</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment"> *</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> * ### How to use ###</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * Suppose `T` is a container type with `Allocator` template param given as `Stateless_allocator&lt;E&gt;`, as well</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * as any nested element types that are also containers also specifying `Allocator` as `Stateless_allocator&lt;...&gt;`.</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> * Suppose you want to work with a `T* t`, such that `t` points to `sizeof(T)` bytes in SHM inside some</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> * #Arena_obj `A`.  In order to perform any work on the `*t` -- including construction, destruction, and any other</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * operations that require internal alloc/dealloc/ptr-deref also inside `A` -- activate `&amp;A` in the relevant</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> * thread using an Arena_activator.  For example:</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> *</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> *   using Shm_classic_arena = classic::Pool_arena;</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> *   template&lt;typename T&gt;</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> *   using Shm_classic_allocator = Stateless_allocator&lt;T, Shm_classic_arena&gt;;</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> *   using Shm_classic_arena_activator = Arena_activator&lt;Shm_classic_arena&gt;;</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> *</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> *   struct Widget { m_float m_a; m_int m_b; }</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> *   using Widget_list = list&lt;Widget, Shm_classic_allocator&lt;Widget&gt;&gt;;</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> *   using Widget_list_vec = vector&lt;Widget_list, Shm_classic_allocator&lt;Widget_list&gt;&gt;;</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> *</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> *   Shm_classic_arena a(...); // Let `a` be a SHM-classic arena storing *x among other things.</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> *</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> *   Widget_list_vec* x = // ...obtain pointer x to SHM-stored space for the Widget_list_vec in question.</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> *   {</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> *     Shm_classic_arena_activator arena_ctx(&amp;a);</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> *     // call x-&gt; ctors, dtor, methods, operators....</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> *   } // Return the active arena to previous value.</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> *   ~~~</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> *</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment"> * Note you may nest Arena_activator contexts in stack-like fashion.  Note, also, that `Arena_activator&lt;A1&gt;`</span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment"> * operates completely independently from `Arena_activator&lt;A2&gt;`, even in the same thread, if `A1` is not same-as</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> * `A2`.  So any &quot;clash&quot; would only occur (1) in a given thread, not across threads; (2) for a given SHM provider</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> * type, not across 2+ such types.</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> *</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment"> * The allocator is *stateless*.  It takes no space within any container that uses it; and it is always default-cted</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"> * by the container code itself -- never by the user.  That is the reason Arena_activator is necessary (when</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment"> * allocating/deallocating).</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"> *</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"> * ### `Arena` type requirements (for full capabilities) ###</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment"> * For write+allocate+deallocate capabilities of Stateless_allocator: an `Arena` must have the following members:</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"> *   - `void* allocate(size_t n);`: Allocate uninitialized buffer of `n` bytes in this SHM arena;</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment"> *     return locally-dereferenceable pointer to that buffer.  Throw exception if ran out of resources.</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> *     (Some providers try hard to avoid this.)</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> *   - `void deallocate(void* p)`: Undo `allocate()` that returned `p`; or the equivalent operation</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> *     if the SHM provider allows process 2 to deallocate something that was allocated by process 1 (and `p` indeed</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> *     was `allocate()`ed in a different process but transmitted to the current process; and was properly made</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> *     locally-dereferenceable before passing it to this method).</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> *   - `template&lt;typename T&gt; class Pointer`: `Pointer&lt;T&gt;` must, informally speaking, mimic `T*`; formally</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> *     being a *fancy pointer* in the STL sense.  The locally-dereferenceable `T*` it yields must point to the</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> *     same underlying area in SHM regardless of in which `Arena`-aware process the deref API is invoked.</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> *     - The `class` keyword is for exposition only; it can also be `using`, `typedef`, or anything else,</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> *       provided it mimics `T*` as described.</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> *     - For example, if #Arena_obj is classic::Pool_arena, then classic::Pool_arena::Pointer might be</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> *       `bipc::offset_ptr`, which internally stores merely an offset within the same SHM-pool versus its own</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> *       `this`; this works great as long indeed the `Pointer` *itself* is located inside the SHM-pool as the</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> *       thing to which it points.</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> *</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> * @todo Currently `Arena::Pointer` shall be a fancy-pointer, but we could support raw pointers also.  Suppose</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> * #Arena_obj is set up in such a way as to map all processes&#39; locally-dereferenceable pointers to the same SHM</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> * location to the same numeric value (by specifying each pool&#39;s start as some predetermined numerical value in</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment"> * the huge 64-bit vaddr space -- in all processes sharing that SHM pool.  Now no address translation is</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment"> * needed, and `Arena::Pointer` could be simply `T*`.  As of this writing some inner impl details suppose</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"> * it being a fancy-pointer, and it&#39;s the only active need we have; but that could be tweaked with a bit of effort.</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment"> *</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment"> * ### Use in read-only borrowing mode ###</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment"> * Taken as an example, SHM-classic (shm::classic::Pool_arena) `Arena`s can always both read and write, allocate and</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment"> * deallocate.  By contrast, shm::arena_lend has allocate/write-capable `Arena` and, on the borrower side,</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment"> * read-only borrower-quasi-`Arena`.  If one needs to merely *read* a SHM-stored STL-compliant structure with such</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment"> * an `Arena`, then **only the `Pointer` type requirement above applies**.</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment"> *   - `allocate()` and `deallocate()` shall not be used by (nor need to be present at compile-time for)</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment"> *     Stateless_allocator.</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment"> *   - No activator -- in fact, no `Arena` *object* -- only the *type*! -- shall be used by Stateless_allocator.</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment"> *</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment"> * @internal</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment"> * ### Implementation ###</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment"> * It is self-explanatory; the trick was knowing what was actually required according to STL-compliance documentation.</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment"> * The great thing is, since C++11, only very few things are indeed needed in our situation; the rest is</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment"> * supplied with sensible default by `allocator_traits` which is how STL-compliant container code actually accesses</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"> * `Allocator`s like ours.</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"> *</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment"> * @endinternal</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment"> *</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment"> * @tparam T</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment"> *         Pointed-to type for the allocator.  See standard C++ `Allocator` concept.</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment"> * @tparam Arena</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment"> *         See above.</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment"> */</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> T, <span class="keyword">typename</span> Arena&gt;</div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">  118</a></span><span class="keyword">class </span><a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator</a></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span>{</div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span>  <span class="comment">// Types.</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment"></span> </div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment">  /// Short-hand for `T`.</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a8bf26ee2ae30dfbe4d64fbcad3ac8368">  124</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a8bf26ee2ae30dfbe4d64fbcad3ac8368">Value</a> = T;</div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"></span> </div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment">  /// Short-hand for the `Arena` type this uses for allocation/deallocation/pointer semantics.</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab8733c1237be93ee28664e4b983d535c">  127</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab8733c1237be93ee28664e4b983d535c">Arena_obj</a> = Arena;</div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"></span> </div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment">  /// The required pointer-like type.  See also #pointer.</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">  130</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">Pointer</a> = <span class="keyword">typename</span> Arena_obj::template <a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">Pointer&lt;Value&gt;</a>;</div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"></span> </div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment">  /// Alias to #Pointer for compatibility with STL-compliant machinery (traits, etc.).</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ae1fc58777e7e727af17fbf0cdaf850bf">  133</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ae1fc58777e7e727af17fbf0cdaf850bf">pointer</a> = <a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">Pointer</a>;</div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment"></span> </div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment">  /// Alias to #Value for compatibility with STL-compliant machinery (traits, etc.).</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#afa85349670ddd8da1eb0386a2556f753">  136</a></span><span class="comment"></span>  <span class="keyword">using </span><a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#afa85349670ddd8da1eb0386a2556f753">value_type</a> = <a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a8bf26ee2ae30dfbe4d64fbcad3ac8368">Value</a>;</div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span> </div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment"></span> </div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="comment">  /// Allocator concept requirement for default-ctor: no-op since it&#39;s a stateless allocator.</span></div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">  141</a></span><span class="comment"></span>  <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">Stateless_allocator</a>();</div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment"></span> </div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment">   * Allocator concept requirement for copy-ctor from allocator-to-another-type: no-op since it&#39;s a stateless</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment">   * allocator.</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="comment">   *</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment">   * @tparam U</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="comment">   *         Like #Value.</span></div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span><span class="comment">   * @param src_ignored</span></div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment">   *        The other allocator.</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment">   */</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> U&gt;</div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">Stateless_allocator</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;U, Arena&gt;</a>&amp; src_ignored);</div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment"></span> </div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment">   * Allocator concept requirement for move-ctor from allocator-to-another-type: no-op since it&#39;s a stateless</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment">   * allocator.</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment">   *</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment">   * @tparam U</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment">   *         Like #Value.</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment">   * @param src_ignored</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span><span class="comment">   *        The other allocator.</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment">   */</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> U&gt;</div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">Stateless_allocator</a>(<a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;U, Arena&gt;</a>&amp;&amp; src_ignored);</div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span> </div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment"></span> </div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment">   * Allocates an uninitialized buffer of given size, or throws exception if `Arena_obj::allocate()` does;</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment">   * satisfies formal requirements of STL-compliant `Allocator` concept.  See cppreference.com for those formal</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment">   * requirements.</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment">   *</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment">   * @param n</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment">   *        The buffer allocated shall be `n * sizeof(Value)`.  Note: This is a #Value count; not a byte count.</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment">   * @return Locally-dereferenceable pointer to the SHM-allocated buffer.</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment">   *         The buffer is *not* initialized.  E.g., depending on the nature of `T` you may want to placement-ct it</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment">   *         at this address subsequently.</span></div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment">   */</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span>  <a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">Pointer</a> <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab8609f6d096e59799d249403905a0953">allocate</a>(<span class="keywordtype">size_t</span> n) <span class="keyword">const</span>;</div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment"></span> </div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment">   * Deallocates buffer in SHM previously allocated via allocate() in this or other (if #Arena_obj supports this)</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment">   * process, as long as `p` refers to the beginning of the buffer returned by that allocate();</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment">   * satisfies formal requirement of STL-compliant `Allocator` concept.  See cppreference.com for those formal</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment">   * requirements.  Does not throw (as required).</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment">   *</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="comment">   * @param p</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="comment">   *        See above.</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment">   * @param n_ignored</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment">   *        Ignored.</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment">   */</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ac6531b5bdb3b299e0780fc5b892bd70c">deallocate</a>(<a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">Pointer</a> p, <span class="keywordtype">size_t</span> n_ignored = 0) const noexcept;</div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span>}; <span class="comment">// class Stateless_allocator</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span> </div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment">// Free functions: in *_fwd.hpp.</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span> </div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment">// Template implementations.</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span> </div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span>template&lt;typename T, typename Arena&gt;</div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab8609f6d096e59799d249403905a0953">  201</a></span>typename <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator</a>&lt;T, Arena&gt;::<a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">Pointer</a> <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator</a>&lt;T, Arena&gt;::<a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab8609f6d096e59799d249403905a0953">allocate</a>(<span class="keywordtype">size_t</span> n)<span class="keyword"> const</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="keyword"></span>{</div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span>  <span class="keyword">const</span> <span class="keyword">auto</span> arena = <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Arena__activator.html#afdce25994086de598aa4c880a6040763">Arena_activator&lt;Arena_obj&gt;::this_thread_active_arena</a>();</div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span>  assert(arena &amp;&amp; <span class="stringliteral">&quot;Before working with SHM-stored STL-compliant objects: activate an Arena via Arena_activator &quot;</span></div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span>                    <span class="stringliteral">&quot;in the thread in question.&quot;</span>);</div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span> </div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span>  <span class="comment">/* void* -&gt; Value* -&gt; Arena::Pointer&lt;Value&gt;.  The last -&gt; is a key, non-trivial operation that creates</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span><span class="comment">   * the SHM-storable fancy-pointer from a locally-dereferenceable raw pointer.  Though typically the fancy-pointer</span></div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment">   * template Arena::Pointer&lt;&gt; would have a ctor that takes a Value*, officially in STL-compliant land it&#39;s</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment">   * the static pointer_to() factory.  pointer_traits&lt;&gt;::pointer_to(T&amp;) does that for non-raw</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment">   * pointers per cppreference.com and also yields a simple &amp;x for raw pointer types (also correct). */</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span>  <span class="keywordflow">return</span> std::pointer_traits&lt;Pointer&gt;::pointer_to</div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span>           (*(<span class="keyword">static_cast&lt;</span><a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a8bf26ee2ae30dfbe4d64fbcad3ac8368">Value</a>*<span class="keyword">&gt;</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span>                (arena-&gt;allocate(n * <span class="keyword">sizeof</span>(<a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a8bf26ee2ae30dfbe4d64fbcad3ac8368">Value</a>))))); <span class="comment">// May throw.</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span>}</div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span> </div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> T, <span class="keyword">typename</span> Arena&gt;</div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ac6531b5bdb3b299e0780fc5b892bd70c">  218</a></span><span class="keywordtype">void</span> <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ac6531b5bdb3b299e0780fc5b892bd70c">Stateless_allocator&lt;T, Arena&gt;::deallocate</a>(<a class="code hl_typedef" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">Pointer</a> p, <span class="keywordtype">size_t</span>) <span class="keyword">const</span> <span class="keyword">noexcept</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span>{</div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span>  <span class="keyword">const</span> <span class="keyword">auto</span> arena = <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Arena__activator.html#afdce25994086de598aa4c880a6040763">Arena_activator&lt;Arena_obj&gt;::this_thread_active_arena</a>();</div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span>  assert(arena &amp;&amp; <span class="stringliteral">&quot;Before working with SHM-stored STL-compliant objects: activate an Arena via Arena_activator &quot;</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span>                    <span class="stringliteral">&quot;in the thread in question.&quot;</span>);</div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span> </div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span>  <span class="comment">/* Arena::Pointer&lt;Value&gt; -&gt; Value* -&gt; void*.  The first -&gt; is a key, non-trivial operation that obtains</span></div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment">   * a locally-dereferenceable raw pointer from the fancy-pointer.  This is expressible generically in a number</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment">   * of ways; but for any fancy-pointer type `.operator-&gt;()` will do it.</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment">   * @todo In C++20 std::to_address() would invoke that for fancy-pointer and simply pass-through the T*</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment">   * for raw pointer.  If we wanted to allow raw pointer support then we&#39;d have to either wait for C++20 and</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment">   * use that helper; or implement it in C++17 ourselves (see cppreference.com for inspiration). */</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span>  arena-&gt;deallocate(<span class="keyword">static_cast&lt;</span><span class="keywordtype">void</span>*<span class="keyword">&gt;</span>(p.operator-&gt;()));</div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span>}</div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span> </div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> T, <span class="keyword">typename</span> Arena&gt;</div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">Stateless_allocator&lt;T, Arena&gt;::Stateless_allocator</a>() = <span class="keywordflow">default</span>;</div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span> </div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> T, <span class="keyword">typename</span> Arena&gt;</div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> U&gt;</div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a07b30ebd16bf82a87186c7baffc9bf85">  238</a></span><a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">Stateless_allocator&lt;T, Arena&gt;::Stateless_allocator</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;U, Arena&gt;</a>&amp;)</div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span>{</div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span>  <span class="comment">// As usual... do nothin&#39;... there&#39;s no state.</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span>}</div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span> </div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> T, <span class="keyword">typename</span> Arena&gt;</div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> U&gt;</div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#aff55fe717e40aca873192819bf1afc15">  245</a></span><a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">Stateless_allocator&lt;T, Arena&gt;::Stateless_allocator</a>(<a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;U, Arena&gt;</a>&amp;&amp;)</div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span>{</div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span>  <span class="comment">// As usual... do nothin&#39;... there&#39;s no state.</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span>}</div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span> </div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Arena, <span class="keyword">typename</span> T1, <span class="keyword">typename</span> T2&gt;</div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a96ccf3e4cf39d59d0a80e9026507b206">  251</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a96ccf3e4cf39d59d0a80e9026507b206">operator==</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;T1, Arena&gt;</a>&amp;, <span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;T2, Arena&gt;</a>&amp;)</div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span>{</div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span>  <span class="keyword">static_assert</span>(std::is_empty_v&lt;Stateless_allocator&lt;T1, Arena&gt;&gt;,</div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span>                <span class="stringliteral">&quot;Stateless_allocator&lt;&gt; is currently designed around being empty (static-data-only) -- &quot;</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span>                  <span class="stringliteral">&quot;did it gain state?&quot;</span>);</div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span>}</div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span> </div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="keyword">template</span>&lt;<span class="keyword">typename</span> Arena, <span class="keyword">typename</span> T1, <span class="keyword">typename</span> T2&gt;</div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno"><a class="line" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab1b059d00a9cbdc54a917e051c1aecdf">  260</a></span><span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab1b059d00a9cbdc54a917e051c1aecdf">operator!=</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;T1, Arena&gt;</a>&amp;, <span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">Stateless_allocator&lt;T2, Arena&gt;</a>&amp;)</div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span>{</div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span>  <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span>}</div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span> </div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span>} <span class="comment">// namespace ipc::shm::stl</span></div>
<div class="ttc" id="aarena__activator_8hpp_html"><div class="ttname"><a href="arena__activator_8hpp.html">arena_activator.hpp</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Arena__activator_html_afdce25994086de598aa4c880a6040763"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Arena__activator.html#afdce25994086de598aa4c880a6040763">ipc::shm::stl::Arena_activator::this_thread_active_arena</a></div><div class="ttdeci">static Arena_obj * this_thread_active_arena()</div><div class="ttdoc">Returns the active arena, as understood by Stateless_allocator&lt;Arena_obj&gt; at this point in the callin...</div><div class="ttdef"><b>Definition:</b> <a href="arena__activator_8hpp_source.html#l00107">arena_activator.hpp:107</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html">ipc::shm::stl::Stateless_allocator</a></div><div class="ttdoc">Stateless allocator usable with STL-compliant containers to store (or merely read) them directly in S...</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00118">stateless_allocator.hpp:119</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_a5ee014d337762aef9c2fbac0585cdfd1"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a5ee014d337762aef9c2fbac0585cdfd1">ipc::shm::stl::Stateless_allocator::Stateless_allocator</a></div><div class="ttdeci">Stateless_allocator()</div><div class="ttdoc">Allocator concept requirement for default-ctor: no-op since it's a stateless allocator.</div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_a8bf26ee2ae30dfbe4d64fbcad3ac8368"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a8bf26ee2ae30dfbe4d64fbcad3ac8368">ipc::shm::stl::Stateless_allocator::Value</a></div><div class="ttdeci">T Value</div><div class="ttdoc">Short-hand for T.</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00124">stateless_allocator.hpp:124</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_a96ccf3e4cf39d59d0a80e9026507b206"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#a96ccf3e4cf39d59d0a80e9026507b206">ipc::shm::stl::Stateless_allocator::operator==</a></div><div class="ttdeci">bool operator==(const Stateless_allocator&lt; T1, Arena &gt; &amp;val1, const Stateless_allocator&lt; T2, Arena &gt; &amp;val2)</div><div class="ttdoc">Returns true for any 2 Stateless_allocators managing the same Stateless_allocator::Arena_obj.</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00251">stateless_allocator.hpp:251</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_ab1b059d00a9cbdc54a917e051c1aecdf"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab1b059d00a9cbdc54a917e051c1aecdf">ipc::shm::stl::Stateless_allocator::operator!=</a></div><div class="ttdeci">bool operator!=(const Stateless_allocator&lt; T1, Arena &gt; &amp;val1, const Stateless_allocator&lt; T2, Arena &gt; &amp;val2)</div><div class="ttdoc">Returns false for any 2 Stateless_allocators managing the same Stateless_allocator::Arena_obj.</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00260">stateless_allocator.hpp:260</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_ab2ed725ef3e8128a35f6ef429fb1fdcb"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab2ed725ef3e8128a35f6ef429fb1fdcb">ipc::shm::stl::Stateless_allocator::Pointer</a></div><div class="ttdeci">typename Arena_obj::template Pointer&lt; Value &gt; Pointer</div><div class="ttdoc">The required pointer-like type. See also pointer.</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00130">stateless_allocator.hpp:130</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_ab8609f6d096e59799d249403905a0953"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab8609f6d096e59799d249403905a0953">ipc::shm::stl::Stateless_allocator::allocate</a></div><div class="ttdeci">Pointer allocate(size_t n) const</div><div class="ttdoc">Allocates an uninitialized buffer of given size, or throws exception if Arena_obj::allocate() does; s...</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00201">stateless_allocator.hpp:201</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_ab8733c1237be93ee28664e4b983d535c"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ab8733c1237be93ee28664e4b983d535c">ipc::shm::stl::Stateless_allocator::Arena_obj</a></div><div class="ttdeci">Arena Arena_obj</div><div class="ttdoc">Short-hand for the Arena type this uses for allocation/deallocation/pointer semantics.</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00127">stateless_allocator.hpp:127</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_ac6531b5bdb3b299e0780fc5b892bd70c"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ac6531b5bdb3b299e0780fc5b892bd70c">ipc::shm::stl::Stateless_allocator::deallocate</a></div><div class="ttdeci">void deallocate(Pointer p, size_t n_ignored=0) const noexcept</div><div class="ttdoc">Deallocates buffer in SHM previously allocated via allocate() in this or other (if Arena_obj supports...</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00218">stateless_allocator.hpp:218</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_ae1fc58777e7e727af17fbf0cdaf850bf"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#ae1fc58777e7e727af17fbf0cdaf850bf">ipc::shm::stl::Stateless_allocator::pointer</a></div><div class="ttdeci">Pointer pointer</div><div class="ttdoc">Alias to Pointer for compatibility with STL-compliant machinery (traits, etc.).</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00133">stateless_allocator.hpp:133</a></div></div>
<div class="ttc" id="aclassipc_1_1shm_1_1stl_1_1Stateless__allocator_html_afa85349670ddd8da1eb0386a2556f753"><div class="ttname"><a href="classipc_1_1shm_1_1stl_1_1Stateless__allocator.html#afa85349670ddd8da1eb0386a2556f753">ipc::shm::stl::Stateless_allocator::value_type</a></div><div class="ttdeci">Value value_type</div><div class="ttdoc">Alias to Value for compatibility with STL-compliant machinery (traits, etc.).</div><div class="ttdef"><b>Definition:</b> <a href="stateless__allocator_8hpp_source.html#l00136">stateless_allocator.hpp:136</a></div></div>
<div class="ttc" id="anamespaceipc_1_1shm_1_1stl_html"><div class="ttname"><a href="namespaceipc_1_1shm_1_1stl.html">ipc::shm::stl</a></div><div class="ttdoc">ipc::shm sub-module providing integration between STL-compliant components (including containers) and...</div><div class="ttdef"><b>Definition:</b> <a href="arena__activator_8hpp_source.html#l00023">arena_activator.hpp:24</a></div></div>
</div><!-- fragment --></div><!-- contents -->
<!-- start footer part -->
<hr class="footer"/><address class="footer"><small>
Generated on Thu May 2 2024 23:56:38 for Flow-IPC by&#160;<a href="https://www.doxygen.org/index.html"><img class="footer" src="doxygen.svg" width="104" height="31" alt="doxygen"/></a> 1.9.4
</small></address>
</body>
</html>
